Dynamo-electric machine



(No Model.) 2 Sheets-Sheet 2. R. H. MATHER.

DYNAMOYBLEGTRIG MACHINE.

No. 268,255. Patented Nov. 28,1882.

0 d ma wm N. PETERS. Pmhmgnph'r, Wanhmgion, D. C.

UNITED STATES RICHARD H. MATHll i, OF \VlNl)SO.lft, CONNECTICUT.

DYNAMO-ELECTRlC NlACi-HNE.

SPECIFICATION forming part of Letters Patent No. 268,255, dated November 28, 1882. Application'filed December 1], i380. (No model.)

To all whom it may concern Be it known that I, Bronnen H. ltia'rurnt, of' Windsor, (post-office address Hartt'ord,) in the county ot' Hartford and State of Connecticut, have invented a certain new and useful Improvement in Dynamo-Electric Machines, of which the following is a description, reference being had to the accompanying drawings, where- Figure l is what may be termed a front View of a machine embodying` my said improvement. Fig. 2 is a side viewot' the same. Fig. 8 is a top or end View ot' the machine. Fig. etis a View of the machine in the same position as in Fig. l, but with the exterior casing and substantially the upper half" ot' the machine represented as cut in vertical section on the plane denoted by the broken line .r a; of Fig. 3. Fig. 5 is a View ofthe machine in vertical section on the plane denoted by the broken line a" x of Fig. Fig. 6 is a view ot' one part of the held-magnet in horizontal section on the plane denoted hy the broken line c rr of Fig. 4. Fig. 7 is a side (front as to position oi" whole machine) view ot' the armature-core, with insulated wire wound thereon. Fig. S is an enlarged peripheral view of the commutator. Fig. J is an enlarged view ot' the commutator cut in axial section. Fig. l() is an end View of the eommutator.

Themachine has a held-magnet in two parts, arranged in the sa megeneral longitudinal line, with the armature located and revolving between them in the same general line or plane.

The armature- One ot' the peculiarities ot' this machine is the armature, the iron core of which is a flat disk, a, cross-mortised at regular intervals on its periphery to hold the coils of insulated'wire in the case where three coils are used, which is the case represented in the drawings. There are six of these cross-morti'ses. Two ot` these mortises are seen in the armaturein Fig. 5. The magnetic axis ot' this disl; is at right angles to the axis ot' rotationi. c., parallel with the plane of rotation. Magnetism seldom or neverextends far beneath the surface ot' a mass ot iron, especially when the iron is in motion. In general magnetism does not extend more than an inch beneath the surface. Hence an armature Ain order to he very etltective (which meansthe production of a high electro-motive force with a short length ot' wire on the armature-core) must have a considerable amount of surface as compared with the amount of metal contained in it. Moreover7 the shape ot' the armature must he such that the wire may be readily coiled upon it.

Perhaps the most important condition as to an armature is that it should need and require 'but a small space for its rotation. Magnetism, like heat, tends to a state of diffusion, never to a state ot' concentration. If an armature is large, it requires a large magnetic field for it to rotate in. That means a great deal ot' iron and copper in the magnets. 1t also means a great many foot-pounds in the current used lo charge the magnets. On the other hand, if' a magnetic field is small it requires out little copper and iron, and but little force to maiutain the current that charges the magnet. It is a general law thata small magnetic field can be more easily maintained than a large but equally intense one. It will therefore be readily comprehended that an armature in the disl; form shown herein meets all the conditions. Nopartot'thedisk-armaturecanescape magnetization. The large surface, combined with the smallthickness. the thickness not exceeding one-third the diameter, insures complete niagnetic saturation. Moreover, there is no screening of one part of the armature by another part, such as is incident to the use ot' the ring and the cylinder forms of armature, in which also there is a great deal ot' space lost within the armatureitsell", owing to its being made hollow; but there would be no usein filling such hollow and making it solid metal, tor the magnetism could not penetrate to such a depth beneath the surface as to utilize such metal. There is no such loss ot' space in a disk-armature, i'or the disk is either made solid or composed of thin plates or laminal separated by noircoinlucting material-paper, forinstance to prevent lL-he circulation ot' electric currents within the armature-core itself. n Fig. 5 ofthe drawings I show the armaturedisk thus made ot metal plates separated by paper plates. .lt is because there is no loss ot' space in this disk-armature that it occupies the least space ot' any armature yet devised, equal currents produced being understood. The number ol" peripheral mortiscs in the disk is proportional to the numberof coilslaid upon the arm ature-two diametrically-opposite morsixth, or sixty degrees, ot' the circuit in cach l by screws s running through the biass edgesemi-rotation it the commutator-plates were all of the same size (which they are) and their lines ot' separation were at right angles to the plane ot' rotation.

Theory and practice both show that the eurieiit in each ot' the armature-coils is prod need or teiidsto be produced duringabout one-tliird or one hundred and twenty degrees ot' the circuit in each semi-rotation, and each setot' the commutator-plates should be in contact with the brushes for the saine duration, in oi der to attain the full efticiency ofthe ariiiaturecoils. To accomplish this it is necessary that each commutator-plate should extend about onethird ofthe entire distance around the circumference of the commutator, and to permit this the lines ot' separation between the commutator-plates are not at right angles to the. pla-ne of rotation, but are at some other angle thereto proporiionetl to the width oi'." these plates and the width ot the brushes. The one essential condition is that the angle shall be such that each commutator-plate shall extend substantially around one-third of the entire circumt'erence ot' the commutator, and this is true whatever the number of armature-coils,

An advantage incident to the construction and operation ot' the armature and commutator lherein described is that the spark generated when a brush quits a commutatorplate can be divided between the two brushes, and its hurtful intluence greatly lessened.

The jieltl-mag-iiet.-Having largely disposed ofthe armature and commutator, I proceed to the held-magnet ot` the machine, which constitutes an important feature ot' the invention. The field-magnet is largely in two parts or poles lying in the same line ot' direction with the armature between them, which in et't'ect is a part of the field-magnet considered as a whole. Each ot' said parts or poles is made up of two or more iron plates disposed side by side, communicatingr by metallic end and edge attachments, but not in directcontact, to the end that air may circulate between the plates.

The letters a and a denote two plates,whieh make up one of said parts or poles, ando and o denote two plates, which make up the other ot' said parts or poles. These plates have a width slightly greater than the diameter ot1 the armature andalength considerably greater than such width. The length ot` these plates -will vary under differentcircumstances, being generally from one and one-half to two times as great as the diameter of the armature. The combined thickness ot these plates isconsiderably greater than the thickness ofthe armature-disk. The ends of these plates next the armature are substantially ofthe shape of the arc of a circle., and in the intermediate circular space the armature is located aud rotates7 the shaft thereof being hung in suitable bearings. lhe plates n it are supported and held in communication at the outer end by screws p running through the end piece i' ofthe general frame of the machine, and on the edges plaies t'. The plates 0 0 are correspondingly supported and held in communication at the outer end by screws p ruiming through the end piece yi" ot' the general traine, and on the edges by the screws s running through the brass edge-plates t.

lt is desirable. that theligurein cross-section formed by the field-magnet parts other than the armature before the insulated wire is wound upon them shall be substaiitialtv the saine as the cross-sectioii shape ot' the armature alter the, wire is laid on it, so that. the coils on the field-magnet can be brought Very near to the armature, and yet have one shape throughout. To bring this about pieces ot' wood it ait/1t, ilat or hollow ou the inner side and convex or curved on the outer side, are disposed at the sides of the lield-iiiagiiet and supported by pins c, with a space between these wooden pieces and the field-magnet plates for tliecirculatiouot' air. Then a coil (oi-coils) of insulated wire, to, is wound over substantially the entire outside of the whole system, secludiiig the armature, as well as the heldinagnetproper,except a small space at the longitudinal center, where the armature-sliat't emerges. In this waythe armature is magnetized directly by the coilsot' the field-magnet, as well as bythe core ot' the ield magnet; but this is not all, indeed but a small part, ot' the advantages which tlow t'roin this construction.

As has hereinbei'ore been stated, magnetism tends to a state ot' dit't'usion; but a state ot concentration can be brought about by proper means7 as well as heat can be concentrated by refraction. The way to prevent ditiusion ot' magnetism is topreient the core from projecting beyond the coil inaguetiziiig it. The farther the core projects beyond the coil the more will the magnetism be diffused. To get the best et't'ect, the end ot the core should be within the cavity oi" the coil. vWhen matters are arranged in this way, which is substantially the arrangement in the construction herein described, the magnetism seems to be concentrated to the very eiidsof the core. Leiigthening the core also has a concentrating ett'ect. then both these means are employed the inagnetic energy is of wonderful intensity. rlhe electric current employed inthe coil surrounding the field-magnet may come either from the current generated by the armature or from a distinct source.

The letters y y denote metallic shells connecting the end pieces, `r and i", and protecting the inclosed parts.

rhe letters .e denote cross-bars forming bearings for the armature-sha t'tI supported from the edge-plates t if.

Thile the coils are moving in t'ront ot' the poles of the field-magnet the coils are activethat is, they are generating electric currentsand the cominutatcr-plates appurteuant to the coils are so located with ret'erence to the points ot' contact with the brushes that the brushes pass from o ne cominiitator-plate to another IOO IOS

IIO

IIS

an armature having a core of circular or simi 1 lar outline on a shai't transverse to thc plane ot' rotation ot' thearmature and placed between the parts ot' thetieldanagnet, the endsoll which i nextthearniaturebeingshapedtoacorrespondi ing;` t=utline,and a circula armaturecorclaterall)v wound with insulated wire, and in turn snrroulnled, so la as practicable, by the tieldmagnet coil or coils-being' found in patent to lhhu Thompson, No. 233,0;417, dated October 5, 1580, I hereblyv disclaim the salue as my invention.

I claim as my inventiontially as described,

1. In a dynamo-electric machine, an armature-core composed of' a disk thel thickness ot' which does not exceed one-third its diameter, and having;` a substantially solid center or interior,aird having eoilsot'insulated wire wound laterali7 thereon, substantially as described.

In adynaino-electricmachine,adisltarmaturecore having peripheral mortises or sock` ets and coils of insulated wire wound into such sockets, substantially as shown and described.

3. In a dynamo-electric niaehine,1he combination of an armature-core, two or more armature-coils, and a commutator having two peripheral plates t'or each armature-coil, respect:- ively connected with the respective ends ot the appurtenant coil, each ot' which plates extends substantially around one-third the circumference ot' the commutator, all substanand for the purpose set forth.

RICHARD Il'. MATHIEU.

Vitnesses: Y

W. E. StttoNDs, JAMES J. GREENE. 

